摘要
本文根据浙江一些典型地开石粘土矿床的化学成分和氢、氧同位素组成等资料,探讨了热液蚀变体系的地球化学特征及其演化过程。着重指出热液流体为来源于中生代大气降水,并在300℃较高温度下与周围岩石发生了同位素交换的循环地热水;然后,在250—100℃的中低温阶段,由该交换后的热液流体蚀变交代酸性火山岩而形成地开石粘土。
Based on chemical composition and hydrogen and oxygen isotopic data of dickite eposits in Zhejiang rovince, this paper discusses geochemical characteristics and evolutionary rocess of their hydrothermal alteration ystem. CIA Calculations and SiO_2/TiO_2-Al_2O_3/TiO_2 iagrams reveal the existence of regular varltion in major re-forming chemical composition from ost rock through altered rock to dickite, suggesting that dickite was formed by ntense ydrothermal alteration of acid volcanic rocks. From the variation curves of isotopic omposition for isotope xchange eqilibrium water between water and wall rock as well as its quilibrium mineral, it is known that hydrthermal luids for alteration came from Mesozoic eteoric water, that cyclic geothermal water underwent isotopic exchange at igher temperature f 00℃, and dickite was formed through alteration by such cyclic geothermal water at esothermal-pithermal stage of 250-100℃. From these data combined with ore deposit geology and alteration ning, his paper makes a brief description of the hydrothermally evolutionary process from the yritization-alunitization-yrophyllitization system in an acid-slightly reducing environment hrough dickite (kaolinite) clayization to ericitization and silicification in a weakly acid-xidizing environment.
出处
《矿床地质》
CAS
CSCD
北大核心
1991年第4期342-348,共7页
Mineral Deposits
